Scanning dental models

ABSTRACT

A system for generating an electronic model having a common coordinate system includes a scanning device; a first plate module; and a second plate module. Each of the plate modules is configured to separately couple to the scanning device. The plate modules also can be moveably coupled together using an articulation device. Each of the plate modules includes alignment structures (e.g., spheres) to facilitate determining a position and orientation of the plate modules within a coordinate system of the scanning device.

TECHNICAL FIELD

This application relates in general to a method and apparatus forproviding electronic models from scanning physical objects, and moreparticularly to a method and apparatus for generating an electronicmodel for a dental impression having a common coordinate system.

BACKGROUND OF THE INVENTION

The use of computer-aided manipulating of electronic models thatcorrespond to physical objects has become more prevalent as thecapabilities of computer processing systems have increased. Thismanipulation began with the modeling and representing of a singlephysical object. In some cases, a physical object has been scanned togenerate an electronic model corresponding to the physical object. Oncea single physical object has been modeled, the development of thesesystems moved to the generation of electronic models for multipleobjects that are physically related. These systems attempt to permit auser to manipulate these multiple objects in a manner that correspondsto the manner in which the physical objects interact with each other inthe physical world.

One such application of this electronic modeling technology is in thedental field in which electronic models are generated that correspond tophysical models made from impressions of teeth in a human mouth. Thesephysical models for patient's teeth have been used by dentists and otherdental health professionals to study the interaction of the opposingjaws before, during, and after treatment plan is implemented. Examplesof uses of these electronic models within the dental field included:U.S. Provisional Patent Application entitled: “METHOD AND APPARATUS FORCOMPUTER GENERATION OF ELECTRONIC MODEL IMAGES”, Ser. No. 60/351,270,filed Jan. 22, 2002, now U.S. application entitled, “METHOD ANDAPPARATUS FOR COMPUTER GENERATION OF ELECTRONIC MODEL IMAGES”, Ser. No.10/350,302, filed Jan. 22, 2003; U.S. patent application entitled,“METHOD AND APPARATUS FOR ELECTRONIC DELIVERY OF DENTAL IMAGES”, Ser.No. 09/846,037, filed Apr. 29, 2001; U.S. patent application entitled,“METHOD AND APPARATUS FOR CONSTRUCTING CROWNS, BRIDGES AND IMPLANTS FORDENTAL USE”, Ser. No. 10/429,288, filed May 2, 2003; U.S. ProvisionalPatent Application entitled , “METHOD AND APPARATUS FOR ELECTRONICALLYSIMULATING JAW FUNCTION”, Ser. No. 60/376,111, filed Apr. 29, 2002, nowU.S. patent application entitled “METHOD AND APPARATUS FORELECTRONICALLY SIMULATING JAW FUNCTION”, Ser. No. 10/426,253, filed Apr.29, 2003; U.S. Provisional Patent Application entitled, “METHOD ANDAPPARATUS FOR ELECTRONICALLY GENERATING A COLOR DENTAL OCCLUSION MAPWITHIN ELECTRONIC MODEL IMAGES”, Ser. No. 60/376,091, filed Apr. 29,2002, now U.S. patent application entitled “METHOD AND APPARATUS FORELECTRONICALLY GENERATING A COLOR DENTAL OCCLUSION MAP WITHIN ELECTRONICMODEL IMAGES, Ser. No. 10/426,252, filed Apr. 29, 2003; and U.S. patentapplication entitled “METHOD AND APPARATUS USING A SCANNED IMAGE FORAUTOMATICALLY PLACING BRACKET IN PRE-DETERMINED LOCATIONS”, Ser. No.10/429,262, filed May 2, 2003, which is a continuation-in-part of U.S.patent application entitled, “METHOD AND APPARATUS USING A SCANNED IMAGEFOR MARKING BRACKET LOCATIONS”, Ser. No. 10/349,559, filed Jan. 22,2003, which claims priority to U.S. Provisional Application entitled,“METHOD AND APPARATUS USING A SCANNED IMAGE FOR MARKING BRACKETLOCATIONS”, Ser. No. 60/351,311, filed Jan. 22, 2002. Additionally,these electronic models may be used as part of data processing of imagesin support of the development of these treatment plans. Examplesinclude: U.S. Provisional Patent Application entitled, “METHOD ANDAPPARATUS FOR AUTOMATICALLY DETERMINING THE LOCATION OF INDIVIDUAL TEETHWITHIN ELECTRONIC MODEL IMAGES”, Ser. No. 60/351,271, filed Jan. 22,2002, now U.S. patent application entitled, “METHOD AND APPARATUS FORAUTOMATICALLY DETERMINING THE LOCATION OF INDIVIDUAL TEETH WITHINELECTRONIC MODEL IMAGES”, Ser. No. 10/350,304, filed Jan. 22, 2003.

Within each of these applications, the scanning of the dental impressionof a patient's mouth produces two separate electronic models that needto be integrated into a single frame of reference if the two models areto be used to interact with each other. This single frame of referencecorresponds to a single coordinate system in which all known points inthe two electronic models for the upper and lower jaws are specified ina single coordinate system. As such, a simple mechanism to determinecommon points in each of the two electronic model coordinate systemssuch that the translation of one coordinate system into the othercoordinate system may be performed easily. In prior art systems, the twoelectronic models were separately generated after which a user wouldidentify common points in the opposing model. Such a system is prone toerror of a user in selecting the common points and as such is notreadily repeatable. As such, there is a further need for a system andmethod to automatically determine a common coordinate system for the twoelectronic models for a patient's mouth when the two physical models arescanned. These and numerous other disadvantages of the prior artnecessitate the need for the method and apparatus provided by thepresent invention.

SUMMARY OF THE INVENTION

This application relates in general to a method and apparatus forgenerating an electronic model for a dental impression having a commoncoordinate system. One possible embodiment of the present invention is asystem for generating an electronic model for a dental impression havinga common coordinate system. The system includes two scanning apparatusfor positioning physical objects within a scanning device whengenerating an electronic model corresponding to each of the physicalobjects; a data processing system for processing the electronic modelscorresponding to each of the physical objects to possess polygonal meshrepresentations of the physical objects within a common coordinatesystem. The scanning apparatus comprises a scanning base plate modulefor coupling the scanning apparatus to the scanning device and aphysical model plate module to coupling the physical object to thescanning base plate module within a coordinate system of the scanningdevice.

Another aspect of the present invention is a method for generating anelectronic model for a dental impression having a common coordinatesystem. The method mounts physical models onto corresponding scanningapparatus, the scanning apparatus positions the physical models within acoordinate system of a scanning device; generates an electronic modelfor each physical model, the electronic models correspond to polygonalmesh representations of scanned position data; positions each of thescanning apparatus into a desired position in which the physical modelsare positioned relative to each other as the objects corresponding tothe physical models interact with each other to generate a compositescanning apparatus; scans a reference point on one or more scanningapparatus within the combined scanning apparatus that are not coupled tothe scanning device; and transforms the electronic models correspondingto the objects having scanning apparatus not coupled to the scanningdevice to generate composite electronic models in a common coordinatesystem.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 a illustrates an example embodiment of an electronic model for anupper and lower jaw impression electronically interacting with eachother according to one possible embodiment of the present invention.

FIG. 1 b illustrates an example embodiment of an electronic model of adental impression used to demonstrate articulation of a jaw andcorresponding teeth according to one possible embodiment of the presentinvention.

FIG. 2 illustrates another example embodiment of an electronic model foran upper and lower jaw impression electronically interacting with eachother according to one possible embodiment of the present invention.

FIG. 3 illustrates a computing system that may be used to constructvarious computing systems that may be part of a distributed processingand communications system according to one embodiment of the presentinvention.

FIG. 4 illustrates a lower jaw dental impression physical model scanningplate apparatus according to an example embodiment of the presentinvention.

FIG. 5 illustrates an upper and a lower jaw dental impression physicalmodel scanning plate apparatus according to an example embodiment of thepresent invention.

FIG. 6 illustrates a spatial transformation for a point located on anupper electronic model from its own coordinate system to a singlecoordinate system.

FIG. 7 illustrates an exploded view for the upper and lower jaw dentalimpression physical model scanning plate apparatus according to anexample embodiment of the present invention.

FIG. 8 illustrates a set of processing modules used within a processingsystem that is part of a system for generating an electronic model fordental impression having a common coordinate system according to anotherexample embodiment of the present invention.

FIG. 9 illustrates an example operation flow for a system for generatingan electronic model for a dental impression having a common coordinatesystem according to one possible embodiment of the present invention.

FIG. 10 illustrates a schematic system in which the approximate locationof the registration/alignment spheres can be determined by finding twoedge points (E1 and E2).

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

This application relates in general to a method and apparatus forgenerating an electronic model for a dental impression having a commoncoordinate system. In the following detailed description of exemplaryembodiments of the invention, reference is made to the accompanieddrawings, which form a part hereof, and which is shown by way ofillustration, specific exemplary embodiments of which the invention maybe practiced. These embodiments are described in sufficient detail toenable those skilled in the art to practice the invention, and it is tobe understood that other embodiments may be utilized, and other changesmay be made, without departing from the spirit or scope of the presentinvention. The following detailed description is, therefore, not to betaken in a limiting sense, and the scope of the present invention isdefined only by the appended claims.

Throughout the specification and claims, the following terms take themeanings explicitly associated therein, unless the context clearlydictates otherwise. The term “connected” means a direct connectionbetween the items connected, without any intermediate devices. The term“coupled” means either a direct connection between the items connected,or an indirect connection through one or more passive or activeintermediary devices. The term “circuit” means either a single componentor a multiplicity of components, either active and/or passive, that arecoupled together to provide a desired function. The term “signal” meansat least one current, voltage, or data signal. Referring to thedrawings, like numbers indicate like parts throughout the views.

FIG. 1 a illustrates an example embodiment of an electronic model for anupper and lower jaw impression electronically interacting with eachother according to one possible embodiment of the present invention. Acomputer-generated image 100 of a pair of electronic modelscorresponding to a patient's upper jaw 101 and lower jaw 102 are shown.These two models are generated separately and then positioned togetherto allow the interaction of the opposing teeth present in the upper jaw101 and the lower jaw 102 electronic models. This interaction of theupper jaw 101 and the lower jaw 102 cannot occur until the coordinatesystems of the two electronic models are combined into a singlecoordinate system.

FIG. 1 b illustrates an example embodiment of an electronic model of adental impression used to demonstrate articulation of a jaw andcorresponding teeth according to one possible embodiment of the presentinvention. In this example embodiment 110, the electronic models for theupper jaw 101 and the lower jaw 102 are super imposed upon an x-ray ofthe patient's skull 120 to allow the two electronic models to be movedrelative to each other about a point of rotation for the jaw 121 in amanner that is consistent with the actual geometry of a patient as shownin the x-ray 120. This movement and interaction of the upper jaw 101 andthe lower jaw 102 also require the use of a common coordinate system forthe electronic models for the upper jaw 101 and the lower jaw 102.Additional details regarding the use of electronic models in thesimulation of teeth and jaw movement relative to each other may be foundwithin U.S. Provisional Patent Application entitled, “METHOD ANDAPPARATUS FOR ELECTRONICALLY SIMULATING JAW FUNCTION”, Ser. No.60/376,111, filed Apr. 29, 2002, now U.S. patent application entitled,“METHOD AND APPARATUS FOR ELECTRONICALLY SIMULATING JAW FUNCTION”, Ser.No. 10/426,253, filed Apr. 29, 2003, both of which are incorporatedherein in their respective entireties.

FIG. 2 illustrates another example embodiment of an electronic model foran upper and lower jaw impression electronically interacting with eachother according to one possible embodiment of the present invention. Inthis embodiment 200, the upper jaw 101 and the lower jaw 102 are shownin a position that corresponds to the position in which the two physicalmodels may be scanned together. In this embodiment 200, the two modelsare shown with a flat surface of the base elements in which theimpressions for the teeth are mounted. The two flat surfaces aretypically shown in a co-planar arrangement with some physical separationfor the two models. While the side surfaces of the base elements containa few co-planar surfaces that allow the registration of the models invarious dimensions, the vertical Z-axis for the two models is notradially detectable. As such, additional steps must be taken totranslate the positions in the two electronic models into a singlecoordinate system. These operations must occur before the two models101-102 may be manipulated as opposing teeth and jaws.

FIG. 3 illustrates a computing system that may be used to constructvarious computing systems that may be part of a distributed processingand communications system according to one embodiment of the presentinvention. In an exemplary embodiment of a processing system 301,computing system 301 is operative to provide a dental scanningcoordinate processing system. Those of ordinary skill in the art willappreciate that the dental scanning coordinate processing system 301 mayinclude many more components than those shown with reference to acomputing system 301 shown in FIG. 3. However, the components shown aresufficient to disclose an illustrative embodiment for practicing thepresent invention. Those of ordinary skill in the art will appreciatethat a network interface unit 310 includes the necessary circuitry forconnecting dental scanning coordinate system processing system 301 to anetwork of other computing systems 305, and is constructed for use withvarious communication protocols including the TCP/IP protocol.Typically, network interface unit 310 is a card contained within neuralnetwork training and data collection system.

Dental scanning coordinate system processing system 301 also includesprocessing unit 312, video display adapter 314, and a mass memory 316,all connected via bus 322. The mass memory generally includes RAM 416,ROM 432, and one or more permanent mass storage devices, such as harddisk drive 328, a tape drive, CD-ROM/DVD-ROM drive 326, and/or a floppydisk drive. The mass memory stores operating system 320 for controllingthe operation of dental scanning coordinate processing system 301. Itwill be appreciated that this component may comprise a general purposeserver operating system as is known to those of ordinary skill in theart, such as UNIX, MAC OS™, LINUX™, OR Microsoft WINDOWS NT®. Basicinput/output system (“BIOS”) 318 is also provided for controlling thelow-level operation of processing system 301.

The mass memory as described above illustrates another type ofcomputer-readable media, namely computer storage media. Computer storagemedia may include volatile and nonvolatile, removable and non-removablemedia implemented in any method or technology for storage ofinformation, such as computer readable instructions, data structures,program modules or other data. Examples of computer storage mediainclude RAM, ROM, EEPROM, flash memory or other memory technology,CD-ROM, digital versatile disks (DVD) or other optical storage, magneticcassettes, magnetic tape, magnetic disk storage or other magneticstorage devices, or any other medium which can be used to store thedesired information and which can be accessed by a computing device.

The mass memory also stores program code and data for providing asoftware development and neural network analysis and training system.More specifically, the mass memory stores applications including commoncoordinate system application program 330, programs 343, and similardata processing applications 336. Common coordinate system applicationprogram 330 includes computer executable instructions which, whenexecuted by computer 301 to perform the logic desired herein.

Dental scanning coordinate system processing system 301 also comprisesinput/output interface 324 for communicating with external devices, suchas a mouse 304, keyboard 303, scanner, or other input devices not shownin FIG. 3. Likewise, a dental scanning coordinate system processingsystem 301 may further comprise additional mass storage facilities suchas CD-ROM/DVD-ROM drive 326 and hard disk drive 328. Hard disk drive 328is utilized by Dental scanning coordinate system processing system 301to store, among other things, application programs, databases, andprogram data used by common coordinate system application program 330.

FIG. 4 illustrates a lower jaw dental impression physical model scanningapparatus according to an example embodiment of the present invention.The apparatus 400 is used to scan a physical impression model for a jaw.In this example, a lower jaw 102 physical model is shown. The apparatuscomprises a scanning base plate module 401 and a physical model platemodule 402. The scanning base plate module 401 is mounted onto ascanning device such that a model that is scanned while attached to theapparatus 400 is located within a known location of the scanning systemcoordinate system. The scanning system is calibrated to know theposition of the scanning base plate 401. The scanning base plate module401 contains an x-axis alignment channel 411 and a y-axis alignmentchannel 410. These two alignment channels are located on the scanningbase plate module 401 in a perpendicular and a co-planar within theplane defined by the top surface of the scanning base plate module 401.These two alignment channels are generally v-shaped such that the vertexof the channel defines the deepest point within the channel.

The physical model plate module 402 comprises a y-axis channel alignmentsphere 421, a first x-axis channel alignment sphere 422, and a secondx-axis channel alignment sphere 423. The physical model plate module 402also comprises a set of physical model attachment devices 431-433 thatare used to secure the physical model 102 into a fixed position on thephysical model plate module 402. The y-axis channel alignment sphere421, the first x-axis channel alignment sphere 422, and the secondx-axis channel alignment sphere 423 are defined by a radiuscorresponding to the size of the two alignment channels within thescanning base plate module 401. These three spheres engage the twoalignment channel to position the physical model plate module 402 at aknown and repeatable position relative to the scanning base plate model401. As such, a scan of a physical model 102 will be at a known positionrelative to the scanning device. This aligned position occurs becausethe first x-axis channel alignment sphere 422 and the second x-axischannel alignment sphere 423 position the physical module plate module402 at a known position relative to the scanning base plate module 401in the x-axis dimension. Similarly, the y-axis channel alignment sphere421 engaging the y-axis alignment channel 410 to position the physicalmodule plate module 402 at a known position relative to the scanningbase plate module 401 in the y-axis dimension. The combination of thetwo alignment channels 410-411 and the three alignment spheres 421-423allows the physical model plate module 402 to be located at a singleposition within a plate parallel to the top of the scanning plate module401.

The same arrangement is used for the opposing physical model 101 using asecond physical model scanning apparatus. From these two apparatus, thetwo separate electronic models are generated having two separatecoordinate systems. These two separate coordinate systems are combinedas discussed below to place all of the points used to define the twoelectronic models within a single coordinate system. Additional detailsregarding the scanning of physical models to generated the electronicmodels may be found in commonly assigned U.S. Provisional PatentApplication entitled, “METHOD AND APPARATUS FOR COMPUTER GENERATION OFELECTRONIC MODEL IMAGES”, Ser. No. 60/351,270 filed Jan. 22, 2002, nowU.S. patent application entitled, “METHOD AND APPARATUS FOR COMPUTERGENERATION OF ELECTRONIC MODEL IMAGES”, Ser. No. 10/350,302, filed Jan.22, 2003, both of which are incorporated herein in their entirety.

FIG. 5 illustrates an upper and lower jaw dental impression physicalmodel scanning plate apparatus according to an example embodiment of thepresent invention. In this example embodiment, the physical modelscanning apparatus 400 discussed in reference to FIG. 4 is shown. Asecond physical model scanning apparatus 500 that contains the opposingphysical model for an upper jaw 101 is also shown. The second physicalmodel scanning apparatus 500 operates identically to the apparatus 400discussed in reference to FIG. 4 for a second physical model.

In this example embodiment, each apparatus 400, 500 also contain anarticulation member 531,532. These two articulation members are coupledtogether to position the upper apparatus 500 at a position relative tothe lower apparatus 400 that simulates the interaction of the upper jawphysical model 101 and the lower jaw physical model 102. By manipulatingthe arrangements of the two articulation members, the two physicalmodels 101, 102 may be positioned into any desired position relative toeach other. The desired position may be defined by a user who moved thetwo apparatus 400, 500 until the two jaw models are in the desiredposition relative to each other. In other embodiments, additional itemssuch as a bite wax impression obtained from the patient may be insertedbetween the two physical models to position them in a desired positioncorresponding to the geometry of the patient's mouth.

It is contemplated herein that other and/or additional records ofpatient's bites could be utilized in connection with developing anddescribing a patient's jaw motion. For example, centric, occlusioncentric relation, protrusive, and lateral excursion (left and/or right)might be used to determine jaw motion. In addition, the system couldmanipulate the jaw image between established positions to obtain anelectronic simulation of jaw motion (e.g., digital articulation).

Once the two apparatus 400-500 are positioned in a desired position, thecombined apparatus may be scanned while attached to the scanning devicewithin the coordinate system used in generating the electronic model 102for the lower jaw to determine the position of the upper apparatus 500within the same coordinate system. When the scanning is performed forthe combined apparatus, only the location of one of the alignmentspheres 521-523 need to be determined. From this additional information,the location of any point on the electronic model 101 for the upper jawmay be expressed in terms of the coordinate system used to define theelectrode model 102 for the lower jaw. This coordinate transformation isillustrated in reference to FIG. 6 below.

FIG. 6 illustrates a spatial transformation for a point located on anupper electronic model from its own coordinate system to a singlecoordinate system. A point Pi 601 on the electronic model for the upperjaw 101 is defined in terms of a common coordinate system having anorigin O. The point Pi 601 is defined as having a position in thiscommon coordinate system Pi=(Xi, Yi, Zi).

In order to define the values that comprise Pi, one needs to combine thevalues of vector Vj 612 with vector Vk 611. Vk 611 is defined in termsof the coordinate system used when the electronic model for the upperjaw was scanned. This vector is known since both the point Pi 601 isknown in the coordinate system used when the electronic model for theupper jaw was scanned and the point Pj 602 is known as the top point onthe sphere 521 in the same coordinate system. This point is known as afixed point in the coordinate system when the alignment spheres areengaged with the alignment channels.

Vector Vj 612 is the value for the location of this top point on sphere521 when the combined apparatus is scanned after the two physical modelsare moved into the desired position. These two vectors, when addedtogether for each location on the upper electronic model 101, transformsall of the coordinates from the two separate coordinate systems into asingle coordinate system.

FIG. 7 illustrates an exploded view for the upper and lower jaw dentalimpression physical model scanning plate apparatus according to anexample embodiment of the present invention. The exploded view includesthe scanning base plate module 401 corresponding to the electronic modelgenerated for the lower jaw model 102; the physical model plate module402 including its three alignment spheres 421-423, and the physicalmodule corresponding to the lower jaw 102. The exploded view of FIG. 7also includes the physical model corresponding to the upper jaw 101 andthe physical model plate module 501 including its three alignmentspheres 521-523 used to generate the electronic model for the upper jaw101. These components work together as discussed above to generate acomposite electronic model for the upper and low jaw of a patient withina common coordinate system.

FIG. 8 illustrates a set of processing modules used within processingsystem that is part of a system for generating an electronic model for adental impression having a common coordinate system according to anotherexample embodiment of the present invention. A dental scanning commoncoordinate system processing system 801 comprises a set of dataprocessing modules that are used to generate the separate upper and lowjaw electronic models and combine the data from these two models into acommon coordinate system. The dental scanning common coordinate systemprocessing system 801 includes a physical model scanning module 811, aphysical model reference point determination module 812, and anelectronic model coordinate system transformation module 813. The dentalscanning common coordinate system processing system 801 also includes aelectronic model database 802 for storing and retrieving electronicmodel data as needed from data storage. In most embodiments, thedatabase is maintained within mass storage devices attached to aprogrammable processing system.

The physical model scanning module 811 interacts with a laser scanningdevice to obtain a set of position data points obtained from thescanning of a physical model. This processing system 801 performs all ofthe processing necessary to reduce this data of location points to anelectronic model defined in a polygonal mesh. These electronic modelsgenerated by this processing module 801 may be stored within theelectronic model database 802 for later use. These electronic models mayalso be passed to the physical model reference point determinationmodule 812, for further processing.

The physical model reference point determination module 812 interactswith the laser scanning device to obtain the location of the referencedata point Pj 602 as discussed above with respect to FIG. 6 on acomposite apparatus. This reference data point Pj 602 is used togenerate the transformation vector Vj 612 that is used to generate thetransformed location data when location data points from an upper jawelectronic model are processed to express location information within acommon coordinate system.

The electronic model coordinate system transformation module 813 usesthe vector Vj 612 determined within the physical model reference pointdetermination module 812 to generate the coordinate data values for eachpoint in an electronic model of an upper jaw 101 within the commoncoordinate system. This module 813 may be used to transform every datapoint within an electronic model before the updated electronic model isstored in the electronic model database 802. Alternatively, this module813 may be used to transform the data points within an area/region ofinterest in the electronic model to allow the process to be completedmore quickly. One skilled in the art will recognize that many differentprocessing mechanisms for generating and applying the transformationvector Vj 612 without deviating from the spirit and scope of the presentinvention as recited within the attached claims.

FIG. 9 illustrates an example operation flow for a system for generatingan electronic model for a dental impression having a common coordinatesystem according to one possible embodiment of the present invention.The process begins 901 and proceeds to operation 911 in which thevarious physical models are mounted on the scanning apparatus that ispart of a scanning device. In completing this operation 911, thephysical models are located within the coordinate system of the scanningdevice for scanning. Next, operation 912 scans the physical models andthen generates the electronic models corresponding to the variousphysical models. These electronic models are expressed as a polygonalmesh that corresponds to the outside surface of the physical objects.

Operation 913 then positions the various physical models into desiredpositions in which the physical models interact with each other in thesame way that the corresponding physical objects interact with eachother. In the dental model processing, the upper and lower physicalmodels are positioned into a position that represents the relationshipof the upper and lower jaw of a patient. This positioning may occur indifferent ways as discussed above with reference to FIG. 6 withoutdeviating from the spirit and scope of the present invention as recitedin the attached claims.

Once the physical models are positioned into the desired locations,operation 914 scans one or more reference points on the combinedscanning apparatus. This scanning may include the scanning of thealignment spheres on a physical model plate module 502 for an upperobject to obtain a point of known position on the upper electronic modelthat is also known within the coordinate system for the upper objectwhen it was scanned individually. This reference point location data isthen used to define a transformation vector Vj as discussed above.

When the transformation vector Vj is defined, operation 915 uses thevector Vj to transform the position location information within theelectronic model of the upper object into corresponding positionlocations within a common coordinate system with the physical objectspositioned at a desired location. Once the position data transformationoperation completes, the process ends 902.

Another feature of the present invention is illustrated in FIG. 10. Hereto reduce the scan time and the time necessary to locate theregistration/alignment spheres, the system may employ an algorithm tolocate two edge points E1 and E2 of the physical model plate module 402.By locating these edge points and recalling the geometry between theedge points, then the first sphere A can be found. The second and thirdsphere's B and C can then subsequently be found.

More specifically, the scanner first finds the surface of the physicalmodel plate module 402 and then begins scanning along a first scan linedesignated at 1001. Once the scanner locates the edge point E1, thescanner steps over and performs a second scan along a second scan linedesignated at 1002. The scan system stores the distance x between thetwo scan lines 1001 and 1002. Once the second edge point E2 is located,a vector E1E2 is determined and the scanner is able to rapidly movealong the vector until it comes to the edge of sphere A. At this time,sphere A is scanned in detail and the location of sphere A is computed.Once vector E1E2 is known and the location of A is known in detail, thenspheres B and C can be located more rapidly.

FIG. 3 illustrates an example of a suitable operating environment inwhich the invention may be implemented. The operation environment isonly one example of a suitable operating environment and is not intendedto suggest any limitation s to the scope of use or functionality of theinvention. Other well known computing systems, environments, and/orconfigurations that may be suitable for use with the invention include,but are not limited to, personal computers, server computers, held-heldor laptop devices, multiprocessor systems, microprocessor-based systems,programmable consumer electronics, network PCs, minicomputers, mainframecomputers, distributed computing environments that include any of theabove systems or devices, and the like.

The invention may also be described in the general context ofcomputer-executable instructions, such as program modules, executed byone or more computers or other devices. Generally, program modulesinclude routines, programs, objects, components, data structures, etc.that perform particular tasks or implement particular abstract datatypes. Typically the functionality of the program modules may becombined or distributed in desired various embodiments.

A processing device attached to a communications network typicallyincludes at least some form of computer readable media. Computerreadable media can be any available media that can be accessed by thesedevices. By way of example, and not limitation, computer readable mediamay comprise computer storage media and communication media. Computerstorage media includes volatile and non-volatile, removable andnon-removable media implemented in any method or technology for storageof information such as computer readable instructions, data structures,program modules or other data. Computer storage media includes, but isnot limited to, RAM, ROM, EEPROM, flash memory or other memorytechnology, CD-ROM, digital versatile disks (DVD) or other opticalstorage, magnetic cassettes, magnetic tape, magnetic disk storage orother magnetic storage devices, or any other medium which can be used tostore the desired information and which can be accessed by processdevices.

Communication media typically embodies computer readable instructions,data structure, program modules or other data in a modulated data signalsuch as a carrier wave or other transport mechanism and includes anyinformation delivery media. The term “modulated data signal” means asignal that has one or more of its characteristics set or changed insuch a manner as to encode information in a signal. By way of example,and not limitation, communication media includes wired media such as awired network or direct-wired connection, and wireless media such as anacoustic, RF, infrared and other wireless media. Combinations of any ofthe above should also be included within the scope of computer readablemedia.

Additionally, the embodiments described herein are implemented as alogical operation performed by a programmable processing device. Thelogical operation of these various embodiments of the present inventionare implemented (1) as a sequence of computer implemented steps orprogram modules running on a computing system and/or (2) asinterconnected machine modules or hardware logic within the computingsystem. The implementation is a matter of choice dependent on theperformance requirements of the computing system implementing theinvention. Accordingly, the logical operations making up the embodimentsof the invention described herein can be variously referred to asoperations, steps, or modules.

While the above embodiments of the present invention describe a system,method and article of manufacture for generating an electronic model fora dental impression having a common coordinate system, one skilled inthe art will recognize that the use of a particular computingarchitecture for a data processing system are merely example embodimentsof the present invention. It is to be understood that other embodimentsmay be utilized and operation changes may be made without departing fromthe scope of the present invention as recited in the attached claims.

As such, the foregoing description of the exemplary embodiments of theinvention has been presented for the purposes of illustration anddescription. They are not intended to be exhaustive or to limit theinvention to the precise forms disclosed. Many modifications andvariations are possible in light of the above teaching. It is intendedthat the scope of the invention be limited not with this detaileddescription, but rather by the claims appended hereto. The presentinvention is presently embodied as a method and apparatus for generatingan electronic model for a dental impression having a common coordinatesystem.

1. A scanning placement system comprising: a first plate moduleincluding a plurality of alignment spheres, the first plate module beingconfigured to couple to a scanning device at a known orientation, thefirst plate module also being configured to retain a first physicalmodel of a first dentition of a patient and to position the firstphysical model on the scanning device within a first coordinate system;and a second plate module including a plurality of alignment spheres,the second plate module being configured to couple to the scanningdevice at a known orientation, the second plate module also beingconfigured to retain a second physical model of a second dentition ofthe patient and to position the second physical model on the scanningdevice within a second coordinate system, the second plate module beingconfigured to operably couple to the first plate module on the scanningdevice to form a combined apparatus within the first coordinate system,the second plate module being moveable with respect to the first platemodule while forming the combined apparatus.
 2. The scanning placementsystem of claim 1, further comprising: a base plate module configured tocouple to the scanning device, the base plate module being configured toreceive a select one of the first plate module and the second platemodule.
 3. The scanning placement system of claim 2, wherein the baseplate module is configured to receive the first plate module when thefirst plate module and the second plate module are coupled together toform the combined apparatus.
 4. The scanning placement system of claim2, wherein the base plate module defines at least a first alignmentchannel.
 5. The scanning placement system of claim 4, wherein the firstalignment channel of the base plate module is configured to receive atleast a first of the alignment spheres of one of the first and secondplate modules.
 6. The scanning placement system of claim 5, wherein thefirst alignment channel is configured to receive at least the first anda second of the alignment spheres of one of the first and second platemodules.
 7. The scanning placement system of claim 4, wherein the baseplate module also defines a second alignment channel orthogonal to thefirst alignment channel.
 8. The scanning placement system of claim 7,wherein a first and a second of the alignment spheres of the first platemodule are configured to cooperatively mate with the first alignmentchannel and a third of the alignment spheres of the first plate moduleis configured to cooperatively mate with the second alignment channel toposition the first plate module at the known orientation.
 9. Thescanning placement system of claim 1, wherein the first dentition of thepatient represents an upper set of teeth of the patient.
 10. Thescanning placement system of claim 9, wherein the second dentition ofthe patient represents a lower set of teeth of the patient.
 11. Thescanning placement system of claim 1, wherein the first physical modelincludes at least one member of the group consisting of a plaster mold,a wax mold, and a plastic mold.
 12. The scanning placement system ofclaim 1, wherein the alignment spheres of the first plate module arearranged along a common plane.
 13. The scanning placement system ofclaim 1, further comprising an articulator to which the first and secondplate modules are to be mounted to form the combined apparatus.
 14. Thescanning placement system of claim 1, further comprising: a dataprocessing system configured to generate electronic model correspondingto each of the physical models within the first coordinate system, thedata processing system being configured to use the scanning device toobtain position data of at least one of the alignment spheres from thecombined scanning apparatus, the data processing system also beingconfigured to transform position data of the first electronic modelobtained from the scanning device and position data of the secondelectronic model obtained from the scanning device based on the positiondata obtained from the alignment sphere, whereby a composite electronicmodel is generated within the first coordinate system.
 15. A methodcomprising: arranging a first physical model on a scanning device, thefirst physical model associated with a first alignment sphere, a secondalignment sphere, and a third alignment sphere; scanning a surface ofthe first physical model along a first scan line to find an edge of thefirst physical model at a first edge point; scanning the surface of thefirst physical model along a second scan line to find the edge of thefirst physical model at a second edge point, the second scan line beingspaced a distance from the first scan line; determining a first vectorcrossing the first edge point and the second edge point, the firstvector having a first direction; locating the first alignment sphere ata first location, the first location being located along the firstvector; and scanning the first alignment sphere to obtain positionaldata.
 16. The method of claim 15, further comprising: locating thesecond alignment sphere based on the first vector and the location ofthe first alignment sphere.
 17. The method of claim 16, furthercomprising: locating the third alignment sphere based on at least thefirst vector and the location of the first alignment sphere.